1. The Field of the Invention
The present invention relates to the field of electronic mail communications. In particular, the present invention relates to the limiting of what an electronic mail recipient may do with an electronic mail message so as to limit the ability to disseminate the electronic mail.
2. Background and Related Art
Electronic mail or “e-mail” has revolutionized the way people communicate. E-mail involves the transmission of messages over networks. The wide proliferation of the Internet allows individuals to communicate via e-mail over vast areas of the globe in a matter of hours, minutes or even seconds depending on the network traffic and server capabilities corresponding to the route the e-mail traverses. Thus, e-mail is characteristically much faster than traditional postal mail. E-mail also does not demand the immediate attention of the recipient as might a telephone call and is considered a polite option where immediate attention is not required. E-mail also allows an electronic record of a chain or “thread” of conversations to be easily maintained thus allowing the reader to review the context of a conversation with relative ease E-mails also may be event driven, in which case an event triggers the transmission of e-mail rather than having a human sender order each e-mail be sent. For these and many other reasons, e-mail has become a major means for communication in the modem world.
Often, even sensitive information is communicated via e-mail. Conventional security methods designed to protect sensitive information include transmitting e-mail in encrypted form, and matching clients and authenticating users before decrypting and delivering the e-mail to an authorized recipient. Unfortunately, however, conventional e-mail technology still allows an authorized recipient to manipulate the e-mail so that unauthorized individuals may view the sensitive information. For example, the e-mail might be copied and pasted into another application, forwarded to unauthorized readers, or printed and distributed to unauthorized readers. Although there are methods for detecting when someone has forwarded a sensitive e-mail, these methods only detect those that have leaked the information, rather than preventing the undesired dissemination of the information in the first place. Therefore, what are desired are ways of preventing the undesired dissemination of e-mail as when the e-mail contains sensitive information that might be harmful if disseminated to unintended readers.